The provincial government should take over responsibility for putting fluoride in city water supplies, Ottawa’s board of health says, joining a campaign that argues local authorities can’t be trusted to keep doing it.

“We wouldn’t leave it up to municipalities to say, should we vaccinate children in this community,” said Barry Ward, a Barrie city councillor and chair of the Simcoe Muskoka health board. The health board, which covers sprawling territory north of Toronto, is dismayed by votes in several of its towns to stop fluoridating water.

“It became apparent to us that it’s become almost impossible to get any community to fluoridate the water,” Ward said. “There would always be a group of citizens who could fill a council chamber, shout down the opposition, and get their way.”

Boards of health include politicians, but they’re supposed to be driven primarily by science, rather than what’s politically appealing. They don’t, however, control the water works.

Having the province take over fluoridation is the solution, the Simcoe Muskoka board says in a position Ottawa’s health board endorsed in an unexpected 5-1 vote Monday night, pulling a letter from Ward out of a sheaf of 15 routine communications and signing on to it.

Dentists and health experts are practically unanimous that fluoridated water is the greatest advance in dental health ever, with hundreds of studies showing it reduces the frequency of cavities by up to 40 per cent wherever it’s been done. Fluoride is cheap (Ottawa spent $374,000 on fluoridation last year) and public-health authorities are adamant that it’s safe in the minute amounts it takes to make a difference to people’s teeth.

For most of the 50 years that Ottawa has been putting fluoride in its water, resisting it has mainly been a pastime of eccentrics. Opposing fluoridation is still at odds with the overwhelming mass of scientific opinion, but it’s taking hold, including among people with the power to do things.

Councillors in Windsor voted to stop fluoridation a year ago. Waterloo did it in 2010 after a city referendum. Huntsville, Baysville and Tottenham, all in Muskoka, are joining. More than 470,000 Ontarians now live in places that used to put fluoride in the water but either have stopped or are about to.

The basic argument against fluoridation has been that fluoride is poisonous in large amounts, the consequences from long-term exposure are uncertain, and forcing people to drink it is an uncontrolled, decades-long experiment with unwilling subjects. A modern variant concedes the value of fluoride but says people can choose to buy fluoridated toothpaste and mouthwashes and public money is better spent on dental treatment specifically for the needy.

Another form of that view has found new life among environmentalists, including Ottawa’s Coun. David Chernushenko, who says he’s “torn” about fluoridation: he appreciates the weight of the scientific evidence in favour of fluoride but as a general principle he’s against putting chemicals into people or nature — in addition to people’s teeth, we’re fluoridating lawns, cars and pools — if it’s not absolutely necessary. He was the one member of Ottawa’s board of health who voted against asking the provincial government to take control of fluoridation.

He’s not an anti-fluoride activist, he’s at pains to say. He just isn’t sure how to decide between the pro- and anti- arguments and didn’t want to make a call on the spot.

“Absolutely there are chemicals that clever humans have come up with that can solve problems we have,” Chernushenko said. “But as with any chemical, fluoride is bound to be making changes to our own chemical makeup. As with so many of these things, we are accepting a risk, knowing there is a benefit.”

We accepted a risk with chemical pesticides for decades before deciding to restrict their use, Chernushenko pointed out. We accepted it with leaded gasoline and we changed our minds about that, too.

“I have accepted that the preponderance of the evidence is that fluoride is a positive thing,” he said. “I just never want to dismiss a group or a point of view as a bunch of kooks who got themselves riled up.”

He understands the challenges the Simcoe Muskoka health unit might have, covering nearly three dozen municipalities with a multitude of fluoridation policies. Ottawa’s health unit deals with Ottawa. “I think Ottawa’s up to it,” he said.

Health Minister Deb Matthews’s office couldn’t say Tuesday whether she’s done anything with Simcoe-Muskoka’s letter, which was sent in January, or what she thinks of the idea that the province should take control of fluoridation.